Great question! Chain catchers can certainly be a valuable addition to your bike, particularly for high-intensity races like criteriums where sudden shifts in power can lead to chain derailments. However, it's important to note that the effectiveness of a chain catcher ultimately depends on factors such as the quality of your bike's components, the maintenance of your chain tensioning, and your own pedaling technique.
Chain catchers work by preventing the chain from falling off the chainring during aggressive shifts or sudden changes in power, which can be especially important in criteriums where riders are constantly jockeying for position and accelerating out of corners. However, it's important to remember that a chain catcher won't prevent all types of chain derailments, such as those caused by a worn-out chain or poor shifting technique.
In terms of drawbacks, chain catchers can add some weight and complexity to your bike's design, and may slightly increase drag or decrease shifting performance in some cases. However, these potential drawbacks are usually relatively minor, and many riders find that the added peace of mind and protection against mechanical failures is worth the trade-off.
Overall, while chain catchers aren't strictly necessary for all riders or all types of riding, they can be a valuable addition to your bike for high-intensity races and other situations where chain derailments are a particular concern. Of course, as with any bike component, it's important to ensure that your bike is properly maintained and set up for optimal performance, regardless of whether or not you choose to use a chain catcher.